added missing input-param to use for places autocomplete endpoint

Hi there, 

i have added the missing Input-Parameter in the Params-Enum to use this library against the Autocomplete-API-Endpoint as documented here [https://developers.google.com/places/documentation/autocomplete?hl=de]

I would much appreciate it if you could check my changes and merge the pull request into the master branch. 
Optionally and a much more appreciated solution would be if also update the supplied aar-libary on maven central with my change. 

ps.: you rock for giving us this library!